Dr. Rosemary Killen
NASA Goddard Space Flight Center
April 5, 3:30 PM
Thirkield Hall (Physics), room 103
Surface-Bounded Exospheres: What are they and why do we care?
An exosphere is a collisionless atmosphere that may
extend from a denser atmosphere or from the surface of a planetary
body. The source processes producing surface-bounded exospheres include
interplanetary radiation, charged particles and interplanetary dust,
meteoroids and asteroids that may impact the surfaces of planets and
satellites. These gaseous envelopes may be bound or escaping.
Exospheres that extend from atmospheres arise mainly due to Jeans
escape (kinetic escape) and charge exchange with ionospheres. I will
discuss the interaction of the interplanetary medium with the planets
and the implications for long-term evolution of the surfaces. Exopheres
from Mercury, the Moon and the satellites of the giant planets will be
Since last year's report, the "small-distance" modifications required by the quantum nature of these models is now also understood and will be presented.
Refreshments will be served at 3:15pm